Bipolar disorder (BPD) is a serious mental illness associated with emotional dysregulation and cognitive impairments. Research suggests that development of BPD has a genetic component and that prefrontal cortical function is strongly implicated in both the emotional and cognitive symptoms of BPD. There is evidence of morphometric abnormalities in the frontal lobes of those with BPD and even in children at familial risk (AR) to develop BPD. To date, no published research has examined in detail the frontal lobe integrity of AR children. The primary goal of this project is to determine what specific prefrontal subregions are morphometrically different in AR children as compared to healthy control (HC) children, whether there are differential gray vs. white matter volumes between the groups, and whether AR children with mood syndromes display a different or more severe pattern of morphometric abnormalities. It is hypothesized that the AR children will demonstrate reduced prefrontal subregion volumes overall with decreased gray matter proportions as compared to HC children, and that AR children with mood syndromes will evidence more pronounced abnormalities. Understanding morphometric abnormalities present in AR children will provide important developmental information regarding the integrity of the brain regions implicated in the development of BPD, will better guide efforts to understand the neuropathology of BPD, and may suggest more focused interventions for the behavioral and cognitive symptoms of this disorder.